rust-agent: Remove or rename unused variables

Remove variables that are simply not used.
Rename as _ variables where only initialization matters.

This addresses the following warnings:

    warning: unused variable: `writer`
       --> src/main.rs:130:9
        |
    130 |     let writer = unsafe { File::from_raw_fd(wfd) };
        |         ^^^^^^ help: if this is intentional, prefix it with an underscore: `_writer`
        |
        = note: `#[warn(unused_variables)]` on by default

    warning: unused variable: `ctx`
       --> src/rpc.rs:782:9
        |
    782 |         ctx: &ttrpc::TtrpcContext,
        |         ^^^ help: if this is intentional, prefix it with an underscore: `_ctx`

    warning: unused variable: `ctx`
       --> src/rpc.rs:808:9
        |
    808 |         ctx: &ttrpc::TtrpcContext,
        |         ^^^ help: if this is intentional, prefix it with an underscore: `_ctx`

    warning: unused variable: `dns_list`
        --> src/rpc.rs:1152:16
         |
    1152 |             Ok(dns_list) => {
         |                ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_dns_list`

    warning: value assigned to `child_stdin` is never read
       --> rustjail/src/container.rs:807:13
        |
    807 |         let mut child_stdin = std::process::Stdio::null();
        |             ^^^^^^^^^^^^^^^
        |
        = note: `#[warn(unused_assignments)]` on by default
        = help: maybe it is overwritten before being read?

    warning: value assigned to `child_stdout` is never read
       --> rustjail/src/container.rs:808:13
        |
    808 |         let mut child_stdout = std::process::Stdio::null();
        |             ^^^^^^^^^^^^^^^^
        |
        = help: maybe it is overwritten before being read?

    warning: value assigned to `child_stderr` is never read
       --> rustjail/src/container.rs:809:13
        |
    809 |         let mut child_stderr = std::process::Stdio::null();
        |             ^^^^^^^^^^^^^^^^
        |
        = help: maybe it is overwritten before being read?

    warning: value assigned to `stdin` is never read
       --> rustjail/src/container.rs:810:13
        |
    810 |         let mut stdin = -1;
        |             ^^^^^^^^^
        |
        = help: maybe it is overwritten before being read?

    warning: value assigned to `stdout` is never read
       --> rustjail/src/container.rs:811:13
        |
    811 |         let mut stdout = -1;
        |             ^^^^^^^^^^
        |
        = help: maybe it is overwritten before being read?

    warning: value assigned to `stderr` is never read
       --> rustjail/src/container.rs:812:13
        |
    812 |         let mut stderr = -1;
        |             ^^^^^^^^^^
        |
        = help: maybe it is overwritten before being read?

Fixes: #750

Signed-off-by: Christophe de Dinechin <dinechin@redhat.com>

src/agent/rustjail/src/container.rs

@@ -799,26 +799,23 @@ impl BaseContainer for LinuxContainer {
             unistd::close(pwfd);
         });
 
-        let mut child_stdin = std::process::Stdio::null();
+        let mut child_stdin: std::process::Stdio;
-        let mut child_stdout = std::process::Stdio::null();
+        let mut child_stdout: std::process::Stdio;
-        let mut child_stderr = std::process::Stdio::null();
+        let mut child_stderr: std::process::Stdio;
-        let mut stdin = -1;
-        let mut stdout = -1;
-        let mut stderr = -1;
 
         if tty {
-            let pseduo = pty::openpty(None, None)?;
+            let pseudo = pty::openpty(None, None)?;
-            p.term_master = Some(pseduo.master);
+            p.term_master = Some(pseudo.master);
-            fcntl::fcntl(pseduo.master, FcntlArg::F_SETFD(FdFlag::FD_CLOEXEC));
+            fcntl::fcntl(pseudo.master, FcntlArg::F_SETFD(FdFlag::FD_CLOEXEC));
-            fcntl::fcntl(pseduo.slave, FcntlArg::F_SETFD(FdFlag::FD_CLOEXEC));
+            fcntl::fcntl(pseudo.slave, FcntlArg::F_SETFD(FdFlag::FD_CLOEXEC));
 
-            child_stdin = unsafe { std::process::Stdio::from_raw_fd(pseduo.slave) };
+            child_stdin = unsafe { std::process::Stdio::from_raw_fd(pseudo.slave) };
-            child_stdout = unsafe { std::process::Stdio::from_raw_fd(pseduo.slave) };
+            child_stdout = unsafe { std::process::Stdio::from_raw_fd(pseudo.slave) };
-            child_stderr = unsafe { std::process::Stdio::from_raw_fd(pseduo.slave) };
+            child_stderr = unsafe { std::process::Stdio::from_raw_fd(pseudo.slave) };
         } else {
-            stdin = p.stdin.unwrap();
+            let stdin = p.stdin.unwrap();
-            stdout = p.stdout.unwrap();
+            let stdout = p.stdout.unwrap();
-            stderr = p.stderr.unwrap();
+            let stderr = p.stderr.unwrap();
             child_stdin = unsafe { std::process::Stdio::from_raw_fd(stdin) };
             child_stdout = unsafe { std::process::Stdio::from_raw_fd(stdout) };
             child_stderr = unsafe { std::process::Stdio::from_raw_fd(stderr) };

src/agent/rustjail/src/mount.rs

@@ -111,6 +111,7 @@ lazy_static! {
 }
 
 #[inline(always)]
+#[allow(unused_variables)]
 fn mount<P1: ?Sized + NixPath, P2: ?Sized + NixPath, P3: ?Sized + NixPath, P4: ?Sized + NixPath>(
     source: Option<&P1>,
     target: &P2,
@@ -125,6 +126,7 @@ fn mount<P1: ?Sized + NixPath, P2: ?Sized + NixPath, P3: ?Sized + NixPath, P4: ?
 }
 
 #[inline(always)]
+#[allow(unused_variables)]
 fn umount2<P: ?Sized + NixPath>(
     target: &P,
     flags: MntFlags,
@@ -421,6 +423,7 @@ fn mount_cgroups(
     Ok(())
 }
 
+#[allow(unused_variables)]
 fn pivot_root<P1: ?Sized + NixPath, P2: ?Sized + NixPath>(
     new_root: &P1,
     put_old: &P2,
@@ -553,6 +556,7 @@ fn parse_mount_table() -> Result<Vec<Info>> {
 }
 
 #[inline(always)]
+#[allow(unused_variables)]
 fn chroot<P: ?Sized + NixPath>(path: &P) -> Result<(), nix::Error> {
     #[cfg(not(test))]
     return unistd::chroot(path);
@@ -1004,8 +1008,8 @@ mod tests {
         // there is no spec.mounts, but should pass
         let ret = init_rootfs(stdout_fd, &spec, &cpath, &mounts, true);
         assert!(ret.is_ok(), "Should pass. Got: {:?}", ret);
-        let ret = fs::remove_dir_all(rootfs.path().join("dev"));
+        let _ = fs::remove_dir_all(rootfs.path().join("dev"));
-        let ret = fs::create_dir(rootfs.path().join("dev"));
+        let _ = fs::create_dir(rootfs.path().join("dev"));
 
         // Adding bad mount point to spec.mounts
         spec.mounts.push(oci::Mount {
@@ -1023,8 +1027,8 @@ mod tests {
             ret
         );
         spec.mounts.pop();
-        let ret = fs::remove_dir_all(rootfs.path().join("dev"));
+        let _ = fs::remove_dir_all(rootfs.path().join("dev"));
-        let ret = fs::create_dir(rootfs.path().join("dev"));
+        let _ = fs::create_dir(rootfs.path().join("dev"));
 
         // mounting a cgroup
         spec.mounts.push(oci::Mount {
@@ -1037,8 +1041,8 @@ mod tests {
         let ret = init_rootfs(stdout_fd, &spec, &cpath, &mounts, true);
         assert!(ret.is_ok(), "Should pass. Got: {:?}", ret);
         spec.mounts.pop();
-        let ret = fs::remove_dir_all(rootfs.path().join("dev"));
+        let _ = fs::remove_dir_all(rootfs.path().join("dev"));
-        let ret = fs::create_dir(rootfs.path().join("dev"));
+        let _ = fs::create_dir(rootfs.path().join("dev"));
 
         // mounting /dev
         spec.mounts.push(oci::Mount {

src/agent/rustjail/src/process.rs

@@ -151,11 +151,11 @@ mod tests {
     #[test]
     fn test_create_extended_pipe() {
         // Test the default
-        let (r, w) = create_extended_pipe(OFlag::O_CLOEXEC, 0).unwrap();
+        let (_r, _w) = create_extended_pipe(OFlag::O_CLOEXEC, 0).unwrap();
 
         // Test setting to the max size
         let max_size = get_pipe_max_size();
-        let (r, w) = create_extended_pipe(OFlag::O_CLOEXEC, max_size).unwrap();
+        let (_, w) = create_extended_pipe(OFlag::O_CLOEXEC, max_size).unwrap();
         let actual_size = get_pipe_size(w);
         assert_eq!(max_size, actual_size);
     }

src/agent/src/main.rs

@@ -129,7 +129,6 @@ fn main() -> Result<()> {
 
     // support vsock log
     let (rfd, wfd) = unistd::pipe2(OFlag::O_CLOEXEC)?;
-    let writer = unsafe { File::from_raw_fd(wfd) };
 
     let agentConfig = AGENT_CONFIG.clone();
 

src/agent/src/mount.rs

@@ -1088,7 +1088,7 @@ mod tests {
 
     #[test]
     fn test_get_cgroup_v2_mounts() {
-        let dir = tempdir().expect("failed to create tmpdir");
+        let _ = tempdir().expect("failed to create tmpdir");
         let drain = slog::Discard;
         let logger = slog::Logger::root(drain, o!());
         let result = get_cgroup_mounts(&logger, "", true);

src/agent/src/rpc.rs

@@ -790,7 +790,7 @@ impl protocols::agent_ttrpc::AgentService for agentService {
 
     fn pause_container(
         &self,
-        ctx: &ttrpc::TtrpcContext,
+        _ctx: &ttrpc::TtrpcContext,
         req: protocols::agent::PauseContainerRequest,
     ) -> ttrpc::Result<protocols::empty::Empty> {
         let cid = req.get_container_id();
@@ -816,7 +816,7 @@ impl protocols::agent_ttrpc::AgentService for agentService {
 
     fn resume_container(
         &self,
-        ctx: &ttrpc::TtrpcContext,
+        _ctx: &ttrpc::TtrpcContext,
         req: protocols::agent::ResumeContainerRequest,
     ) -> ttrpc::Result<protocols::empty::Empty> {
         let cid = req.get_container_id();
@@ -1160,7 +1160,7 @@ impl protocols::agent_ttrpc::AgentService for agentService {
         };
 
         match setup_guest_dns(sl!(), req.dns.to_vec()) {
-            Ok(dns_list) => {
+            Ok(_) => {
                 let sandbox = self.sandbox.clone();
                 let mut s = sandbox.lock().unwrap();
                 let _ = req